Yes, which is a huge problem. This is a big part of why Android phones suck so much ass - you're often stuck on old versions of android because the hardware vendors are too lazy to update their proprietary bullshit blobs that barely fucking work.

And now you're running a two year old phone and it's effectively obsolete.

If they would just upstream their firmware into the Linux kernel, you could upgrade these phones for years and years. Until the hardware is actually physically incapable of running the latest features.

Some vendors, like Google, promise to provide updates for a long time. But it's just that - a promise. There's no technical guarantee or mechanism for this, it's purely based on trust.